Trial registration and adherence to reporting guidelines in cardiovascular journals.

Objective: This study investigated the policies of cardiac and cardiovascular system journals concerning clinical trial registration and guideline adoption to understand how frequently journals use these mechanisms to improve transparency, trial reporting and overall study quality.

Methods: We selected the top 20 (by impact factor) journals cited in the subcategory 'Cardiac and Cardiovascular Systems' of the Expanded Science Citation Index of the 2014 Journal Citation Reports to extract journal policies concerning the 17 guidelines we identified. In addition, trial and systematic review registration adherence statements were extracted.

The association of the mitochondrial DNA OriB variant (16184-16193 polycytosine tract) with type 2 diabetes in Europid populations.

Aims/hypothesis: The association between the mitochondrial DNA 16181-16193 polycytosine variant (known as the OriB variant as it maps to the OriB origin of replication) and type 2 diabetes has not been reliably characterised, with studies reporting conflicting results. We report a systematic review of published literature in Europid populations, new data from the Norfolk Diabetes Case-Control Study and a meta-analysis to help quantify this association.

Methods: We performed a systematic review identifying all the studies of the OriB variant and type 2 diabetes in Europid populations published before January 2013.

Sources of pre-analytical variations in yield of DNA extracted from blood samples: analysis of 50,000 DNA samples in EPIC.

The European Prospective Investigation into Cancer and nutrition (EPIC) is a long-term, multi-centric prospective study in Europe investigating the relationships between cancer and nutrition. This study has served as a basis for a number of Genome-Wide Association Studies (GWAS) and other types of genetic analyses. Over a period of 5 years, 52,256 EPIC DNA samples have been extracted using an automated DNA extraction platform.